Adsorbents　with　good　dispersibility　and　high　efficiency　are　crucial　for　magnetic　solid-phase　extraction　(MSPE).　In　this　study,　flower-like　magnetic　nanomaterials　(F-Ni@NiO@ZnO2-C)　were　successfully　prepared　by　calcination　of　metal-organic　framework　(MOF)　precursors　that　was　stacked　by　two-dimensional　(2D)　nanosheet.　The　synthesized　F-Ni@NiO@ZnO2-C　has　a　flower-like　layered　structure　with　a　large　amount　of　pore　space,　promoting　the　rapid　diffusion　of　targets.　In　addition,　Zn2+　doped　in　MOF　precursors　was　still　retained　that　further　produced　strong　metal　chelation　with　targets.　The　unique　structure　of　F-Ni@NiO@ZnO2-C　was　used　as　MSPE　adsorbent,　and　combined　with　high-performance　liquid　chromatography-tandem　mass　spectrometry　(HPLC-MS/MS)　for　extraction　of　three　microcystins　(MCs)　detection,　including　microcystin-LR　(MC-LR),　microcystin-RR　(MC-RR),　microcystin-YR　(MC-YR).　The　resulting　method　has　a　detection　limit　of　0.2–1.0　pg　mL−1,　a　linear　dynamic　range　of　0.6–500.0　pg　mL−1　and　has　good　linearity　(R　≥　0.9996).　Finally,　the　established　method　was　applied　to　the　highly　selective　enrichment　of　MCs　in　biological　samples,　successfully　detecting　trace　amounts　of　MCs　(8.4–15.0　pg　mL−1)　with　satisfactory　recovery　rates　(83.7–103.1　%).　The　results　indicated　that　flower-like　magnetic　F-Ni@NiO@ZnO2-C　was　a　promising　adsorbent,　providing　great　potential　for　the　determination　of　trace　amounts　of　MCs　in　biological　samples.　©　2024　Elsevier　B.V.